Ro(o)ney's were Catholic - try Brian Lawson's new index to RC marriages/baptisms
http://www.lawsons.ca/19_century/rc_marriage.html and http://www.lawsons.ca/19_century/dis_births.html
however these give out at 1849 - between then and 1877 (civil) you need Bap reg from St Mary's RC which is not on-line nor in IGI
(they were mainly grocers in Douglas - several buried in a corner of St Georges churchyard (at that time not consecrated thus legally I guess the RC priest could officiate)